The plaintiffs are seeking an injunction to prevent the law from being enacted while the case is litigated.

“The danger, if the state prevails and we lose, is it demonstrates the ways in which the legislative process can be manipulated,” Cooper said.

In passing the “Improving Education Stability for Foster Youth” bill, lawmakers made it easier for about 6,000 students in foster care statewide to attend their school of origin, regardless of where they live.

Foster children have a 55 percent mobility rate, according to the Colorado Department of Education.

Providing such educational stability while children move from foster home to foster home is expected to improve academic performance and those students’ graduation rate, which is about 37 percent statewide.

But before the session ended May 9, state Sen. Owen Hill, R-Colorado Springs, inserted an amendment, using the language from a rejected bill he had sponsored about providing free transportation across districts to “improve school choice.”

Hill said Friday that, after consulting with lawyers, it was the only way to write the addition to cover transportation for foster care students, and that accusations that it was a sneaky way to insert a controversial school choice provision are “completely unfounded.”

“The idea was, if we’re to help foster kids, we can’t put all these bureaucratic burdens in place,” he said. “We can’t say with one hand, ‘We’re out there to help foster kids,’ and on the other hand, ‘We’re not going to allow kids to cross district lines.’ It’s inconsistent.”

The bill passed 35-0 in the Senate and had 100 percent support in the House, he added.

But that clause made a “significant change” regarding inter-district student transportation, Colorado Education Commissioner Katy Anthes said in an email sent Thursday to superintendents.

Anthes said she and the state Board of Education are named as defendants, not because either has taken a position on the bill, but “because of our state constitutional responsibilities for the general supervision of the public schools.”

The new law says school boards “may furnish transportation to and from public schools” for all students — not only foster kids — who are enrolled in the district but live in another district.

Until now, school districts could transport nonresident students only if they lived in an adjacent district whose school board gave approval.

The lawsuit argues that Hill’s amendment is “legally void,” given that under Colorado law, bills must contain “only one subject that is clearly expressed in the bill’s title.”

When signing the bill, Gov. John Hickenlooper expressed concern that the new section would be vulnerable to a legal attack based on the “single subject” requirement.

Some have lauded the change, calling it a victory for school choice.

Colorado Succeeds, a nonprofit, nonpartisan organization of business leaders promoting education, said on its website that lifting “transportation barriers” will “help provide more equitable access to schools for low- and middle-income students by expanding transportation options — the historical reason some children have had barriers to true school choice.”

But that’s disputed by plaintiffs in the lawsuit, which also include the Colorado Association of School Executives, the Colorado Association of School Boards, Englewood Schools, Sheridan School District 2, Monte Vista School District C-8, Poudre School District R-1, Jefferson County Public Schools, its superintendent and a board member.

If the plaintiffs win, the law would revert to prohibiting transporting students across district boundaries without permission from the other school district, Anthes cautioned superintendents in her letter.

Should the new law remain in place, the effect of the change would vary widely, said Cooper, Colorado’s 2018 Superintendent of the Year, who frequently testifies at the Capitol on legislative issues.

Cheyenne Mountain D-12, in southwest Colorado Springs near the Skyway and Broadmoor neighborhoods, does not bus students, he said, and doesn’t have an issue with other districts trying to lure students to their schools.

“We’re not concerned with protecting our enrollment. We have three times as many choice students enrolling into District 12 than we have choosing to enroll outside of the district, and we have far more requests than we can honor,” he said.

But having buses from other districts come to pick up students and transport them elsewhere is a problem for some.

A few years ago, Ellicott School District 22, an eastern El Paso County district with about 1,000 students, denied a request from neighboring School District 49 to cross Ellicott’s boundaries and shuttle students to a new charter school that was scheduled to open in D-49.

“When you bring a bus into our district and take our students to a charter school outside our district, you hurt our community and our schools,” said Superintendent Chris Smith.

“I don’t have a huge marketing department that can compete for those students.”

Being a foster child until age 15, when he was adopted, Smith said he’s in favor of the portion of the bill that seeks to remove barriers for foster students to succeed in school.

“I understand that consistency of being in your neighborhood district, and I’m sympathetic to that,” he said.

“I agree with school choice, but I don’t agree with language that was put in the bill. It picks off our kids in our district, and that’s hard for us.”

Each year, about 100 kids, or 10 percent of enrollment, choice into Ellicott D-22.

“I wouldn’t expect to take my business into another district and pull students out,” he said. “I wish it wasn’t so territorial.”

The amendment also says a school board may reimburse parents for expenses incurred in furnishing transportation to and from public school or a designated school bus stop for their own children or other pupils.